I am now of the strict opinion that my F2 i snot stock. I have never come up against another 600 as fast as mine, and yesterday i raced a guy with a ZX-7R (750cc) and I very slowly walked away from him. We pulled several times from roll-ons of different speeds with the same outcome. He was regeared same as me, -1+2, has an all alum bike and weighs almost 200lbs less than me....... I'm dumbfounded as to what is in my bike to make it so freaking fast.

I am looking for ways to determine if it has a big bore kit / cams without actually tearing it down. I am also currious what other mods could account for this, I know it has K&N filter, V&H SS2R (I removed the baffle and it runs MUCH better now) and -1+2 gears with a 530 chain and Alum sproket.

I have noticed it does not run quite right on 87 r+m/2, but there are so many variables there I always just dismissed it and ran 89 or better as a rule (local gas station sells 89 and 87 at the same price).

 

^^^why run such low octane gas?

 

You could look around the motor for signs of it being resealed, ie RTV oozed out. Other than that, you'd have to tear it down most likely. Or dyno?

 

id say a dyno run. i just did the same thing because i was getting the same result as you, i beat an 09zx6 with my f4 from a first gear roll to about 150ish, also destroyed another f4i same year with less miles again from a first gear roll. it only dynoed 93.69, and the other f4i put down 91.xx. no idea why mine rides out harder than any other 600 ive come up to so far, and i had a gixxer 750 -1/+2 that pulled away slowly.

 

you could be just a better rider. they say you only use 10% of your brain, i'd like to think that this applies the same to a bikes horsepower.

 

well got some news for you.. back when the F2 was new it hade a much better Power-to-weight ratio then any 750 of the day so just about in any race condition the f2 would kick *** and take names..this was really true with the 750s from 91-95. what year zx-7 was it??

 

My buddy's 93 zx7 with pipe and jet kit dynoed at 107 back in 95. I think they were about 50 pounds heavier than F2's. F2 had almost 90 hp with pipe and jet kit. 100hp if big bore +2mm and some mild head work. Do the math. And of course the biggest factor, the rider. You figure Valentino Rossi on a moped would smoke most of us on our cbr's

 

i tuned alot of 93/95 zx-7s and after jet kit and pipe yes 107/108h.p witch was concedered great for the day and becouse the 91/92s were only about 95 rwhp and about 60 pounds heaver..i did alot of drag racing back in them days with my 94F2 and never hade a 750 beat an f2 in 1/4mile.. a good mod to do to the zx7s was to drop it -1 in the front... back then 750s were really known for the hardware that they came with stock..

 

The ZX-7R was the 93-95 body style.

The owner stated he was geared -1+2

I was of the understanding that these bikes are good to run on 87 r+m/2, higher octane would then just be a waste of $$$$$$ (which I have entirely too little of).

My bike does have yellow grease marker inside the case. I noticed it when doing clutch / shift star. It appears to be assembly reference markings. I assumed they were factory....

I would have thought, with my dumb ideas, that the ZX-7R being all alum (frame / swingarm) vs. our steel would be lighter. I understand it is 150cc larger and that increase comes with some extra mass, but thought at worst case they would weigh the same. ( I still have around 150 pounds on the other guy or shear rider weight at my feather weight 315)

Closest Dyno that will let me run a bike is a couple hours away. I forget the cost, but it isn't cheap. I was hoping to have my carbs professionally tuned while I was there, but again with the $$$$$$.

What about a compression test? What should stock compression be (I am at work and do not have a manual at hand)? And what would it be with big bore / high c/r pistons?

 

So how far did you run them up too? That zx-7 sould have started pulling on you hard after 120mph. I had a 93,and it would do an indicated 175mph on the speedo. I also outran my buddies brand new CBR 900rr from about a 50 roll.